1. Field of the Invention
The present invention relates to a liquid crystal display panel driving circuit, and more particularly, to a liquid crystal display panel driving circuit with a significantly reduced area.
2. Description of the Related Art
Recently, the resolution of a display panel such as a television has been increased day by day. With the increase in the resolution of the display panel, the size of a driving circuit for driving a panel in a source driver IC (integrated circuit) of a display apparatus has also been increased.
In such a liquid crystal display panel driving circuit, the area of a circuit is an important factor. When the size of the driving circuit is increased, since the manufacturing cost of the liquid crystal display driving circuit and system is increased and thus competitiveness thereof is reduced, technologies for reducing the area of the liquid crystal display driving circuit are required.
FIG. 1 is a diagram illustrating one example of a liquid crystal display panel driving circuit in accordance with the related art.
The liquid crystal display panel driving circuit 100 illustrated in FIG. 1 includes a resistor string unit 110, DAC (digital-to-analog converter) switching units 121 and 122, buffers 131 and 132, and an output switching unit 140.
The resistor string unit 110 and the digital to analog converter switching units 121 and 122 will be collectively referred to as a resistor DAC.
The resistor string unit 110 includes resistors serially connected to one another. When N-bit digital data is inputted, since the resistor string unit 110 includes 2N resistors and generates different reference voltages at respective connection nodes among the resistors, 2N reference voltages can be generated.
In the liquid crystal display panel driving circuit, the first DAC switching unit 121 receives digital data from a timing controller, selects a single analog reference voltage corresponding to the digital data from the 2N reference voltages generated by the resistor string unit 110, and outputs the selected reference voltage, and the buffer 131 drives the load of the data line of a liquid crystal display panel.
According to an image display scheme of the liquid crystal display panel, since output of the liquid crystal display panel driving circuit is used for driving different pieces of data and an image is displayed through a combination of colors according to each data, a DAC and a buffer (or an amplifier) are necessarily provided for each output corresponding to inputted digital data (refer to the first DAC switching unit 121 and the mth DAC switching unit 122, and the buffers 131 and 132 in FIG. 1).
The most important factor for the resolution of the liquid crystal display panel is the resolution of the DAC. As the resolution of the DAC is increased, natural color sense can be achieved.
However, in order to increase the resolution of the DAC, the bit number N of inputted digital data increases and thus the number of resistors required for the resistor string unit 110 and transistors constituting the DAC switching unit increases by geometric progression, resulting in an increase in the area of the driving circuit. As a result, the manufacturing cost may increase.